Question

Which type of remote sensing system uses its own source of energy?

• A. Passive remote sensing
• B. Optical remote sensing
• C. Active remote sensing
• D. Thermal remote sensing

Hint:

Active systems like RADAR have a major advantage: they can operate during the day or night and can "see" through clouds and rain, unlike passive optical sensors which require sunlight and clear skies.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Remote sensing systems are categorized based on the source of electromagnetic radiation used to illuminate the target.
Step 2: Detailed Explanation:
1. Passive Remote Sensing: These sensors detect energy that is naturally available. Most often, this is reflected sunlight or thermal energy emitted from the Earth's surface. Examples include standard satellite cameras and thermal infrared sensors.
2. Active Remote Sensing: These systems provide their own energy source for illumination. The sensor emits radiation (usually in the form of pulses) directed toward the target and then detects the radiation reflected or backscattered from that target.
Common examples of active systems include:
- RADAR (Radio Detection and Ranging)
- LiDAR (Light Detection and Ranging)
- SONAR (Sound Navigation and Ranging)
Step 3: Final Answer:
Active remote sensing systems are the ones that use their own source of energy.